Approximate the following integrals using either the midpoint rule, trapezoidal rule, or Simpson’s rule as indicated. (Round answers to three decimal places.)
1. [latex]{\displaystyle\int }_{1}^{2}\frac{dx}{x}[/latex]; trapezoidal rule; [latex]n=5[/latex]
3. [latex]{\displaystyle\int }_{0}^{3}\sqrt{4+{x}^{3}}dx[/latex]; Simpson’s rule; [latex]n=3[/latex]
5. [latex]{\displaystyle\int }_{0}^{1}{\sin}^{2}\left(\pi x\right)dx[/latex]; midpoint rule; [latex]n=3[/latex]
11. Use the trapezoidal rule with four subdivisions to estimate [latex]{\displaystyle\int }_{2}^{4}{x}^{2}dx[/latex].
Approximate the integral to three decimal places using the indicated rule.
13. [latex]{\displaystyle\int }_{0}^{1}{\sin}^{2}\left(\pi x\right)dx[/latex]; trapezoidal rule; [latex]n=6[/latex]
15. [latex]{\displaystyle\int }_{0}^{3}\frac{1}{1+{x}^{3}}dx[/latex]; Simpson’s rule; [latex]n=3[/latex]
17. [latex]{\displaystyle\int }_{0}^{0.8}{e}^{\text{-}{x}^{2}}dx[/latex]; Simpson’s rule; [latex]n=4[/latex]
19. [latex]{\displaystyle\int }_{0}^{0.4}\sin\left({x}^{2}\right)dx[/latex]; Simpson’s rule; [latex]n=4[/latex]
21. [latex]{\displaystyle\int }_{0.1}^{0.5}\frac{\cos{x}}{x}dx[/latex]; Simpson’s rule; [latex]n=4[/latex]
23. Approximate [latex]{\displaystyle\int }_{2}^{4}\frac{1}{\text{ln}x}dx[/latex] using the midpoint rule with four subdivisions to four decimal places.
25. Use the trapezoidal rule with four subdivisions to estimate [latex]{\displaystyle\int }_{0}^{0.8}{x}^{3}dx[/latex] to four decimal places.
27. Using Simpson’s rule with four subdivisions, find [latex]{\displaystyle\int }_{0}^{\frac{\pi}{2}}\cos\left(x\right)dx[/latex].
29. Given [latex]{\displaystyle\int }_{0}^{1}x{e}^{\text{-}x}dx=1-\frac{2}{e}[/latex], use the trapezoidal rule with 16 subdivisions to approximate the integral and find the absolute error.
31. Find an upper bound for the error in estimating [latex]{\displaystyle\int }_{4}^{5}\frac{1}{{\left(x - 1\right)}^{2}}dx[/latex] using the trapezoidal rule with seven subdivisions.
33. Find an upper bound for the error in estimating [latex]{\displaystyle\int }_{2}^{5}\frac{1}{x - 1}dx[/latex] using Simpson’s rule with [latex]n=10[/latex] steps.
35. Estimate the minimum number of subintervals needed to approximate the integral [latex]{\displaystyle\int }_{1}^{4}\left(5{x}^{2}+8\right)dx[/latex] with an error magnitude of less than 0.0001 using the trapezoidal rule.
37. Estimate the minimum number of subintervals needed to approximate the integral [latex]{\displaystyle\int }_{2}^{3}\left(2{x}^{3}+4x\right)dx[/latex] with an error of magnitude less than 0.0001 using the trapezoidal rule.
39. Use Simpson’s rule with four subdivisions to approximate the area under the probability density function [latex]y=\frac{1}{\sqrt{2\pi }}{e}^{\frac{\text{-}{x}^{2}}{2}}[/latex] from [latex]x=0[/latex] to [latex]x=0.4[/latex].
41. The length of one arch of the curve [latex]y=3\sin\left(2x\right)[/latex] is given by [latex]L={\displaystyle\int }_{0}^{\frac{\pi}{2}}\sqrt{1+36{\cos}^{2}\left(2x\right)}dx[/latex]. Estimate L using the trapezoidal rule with [latex]n=6[/latex].
43. Estimate the area of the surface generated by revolving the curve [latex]y=\cos\left(2x\right),0\le x\le \frac{\pi }{4}[/latex] about the x-axis. Use the trapezoidal rule with six subdivisions.
45. The growth rate of a certain tree (in feet) is given by [latex]y=\frac{2}{t+1}+{e}^{\frac{\text{-}{t}^{2}}{2}}[/latex], where t is time in years. Estimate the growth of the tree through the end of the second year by using Simpson’s rule, using two subintervals. (Round the answer to the nearest hundredth.)
47. [T] Given [latex]{\displaystyle\int }_{1}^{5}\left(3{x}^{2}-2x\right)dx=100[/latex], approximate the value of this integral using the trapezoidal rule with 16 subdivisions and determine the absolute error.
49. The table represents the coordinates [latex]\left(x,\text{ }y\right)[/latex] that give the boundary of a lot. The units of measurement are meters. Use the trapezoidal rule to estimate the number of square meters of land that is in this lot.
x | y | x | y |
---|---|---|---|
0 | 125 | 600 | 95 |
100 | 125 | 700 | 88 |
200 | 120 | 800 | 75 |
300 | 112 | 900 | 35 |
400 | 90 | 1000 | 0 |
500 | 90 |
50. Choose the correct answer. When Simpson’s rule is used to approximate the definite integral, it is necessary that the number of partitions be____
- an even number
- odd number
- either an even or an odd number
- a multiple of 4
51. The “Simpson” sum is based on the area under a ____.
52. The error formula for Simpson’s rule depends on___.
- [latex]f\left(x\right)[/latex]
- [latex]{f}^{\prime }\left(x\right)[/latex]
- [latex]{f}^{\left(4\right)}\left(x\right)[/latex]
- the number of steps
Candela Citations
- Calculus Volume 2. Authored by: Gilbert Strang, Edwin (Jed) Herman. Provided by: OpenStax. Located at: https://openstax.org/books/calculus-volume-2/pages/1-introduction. License: CC BY-NC-SA: Attribution-NonCommercial-ShareAlike. License Terms: Access for free at https://openstax.org/books/calculus-volume-2/pages/1-introduction